apply PageTransformer to PagerView as soon as possible

Question

I have a PageTransfomer applied to a ViewPager, it works great but I want to launch the page's transformation as soon as I set the PageTransformer to the ViewPager. I already tried:

• setCurrentItem(int)
• setCurrentItem(int, true)
• beginFakeDrag(), fakeDragBy(float), endFakeDrag()
• invalidate()
• getAdapter().notifyDataSetChanged()

I've tried all these in the onCreate of my activity but maybe I'm wrong.

Does anyone have a clue ?

Thanks

Answer 1

Based on Oleg's answer is used the code below for my app.

My addition is to check the returned result of beginFakeDrag() inside _invalidatePageTransformer.

I call sendInvalidatePageTransformer() from inside

• onConfigurationChanged() when the orientation changed

• inside the LoaderCallback<Cursor>-methods in my Fragment

  private Handler handler = new Handler()
  {
          public void handleMessage(Message msg)
          {
                  switch(msg.what)
                  {
                          case 0:
                                  _invalidatePageTransformer();
                                  break;
                  }
          }
  };
  
  private void _invalidatePageTransformer()
  {
          //no need to invalidate if we have no adapter or no items
          if (this.getAdapter() != null && this.getAdapter().getCount() > 0)
          {
                  //import check here, only fakeDrag if "beginFakeDrag()" returns true
                  if (this.beginFakeDrag())
                  {
                          this.fakeDragBy(0f);
                          this.endFakeDrag();
                  }
          }
  }
  
  public void sendInvalidatePageTransformer()
  {
          this.handler.sendEmptyMessage(0);
  }
  

EDIT: Note: This code is located inside a custom ViewPager-subclass

Answer 2

Try one of these things:

1. Put the code in onPostCreate()
2. Put the code in a handler; i.e. new Handler().post(new Runnable() { /* your code */ });